This invention relates to lighting devices, to electric lamps and, more particularly, to an electric lamp assembly for use on motor vehicles. Still more particularly, the electric lamp assembly in accordance with the invention is equipped with a lamp cover which is powered for automatically uncovering the lamp when the same is lit up.
Some vehicular lighting devices, such as fog lamps and cornering lamps, are lit up occasionally rather than continuously or at very short intervals. When unlit, therefore, they should be covered for protection of their front lenses from dust, rain, snow, and stones or other matter that have been thrown up by other vehicles. Such lamps are usually lit up by the driver when the vehicle is running. Their front lenses should therefore be automatically uncovered when the lamps are switched on, and should be covered again when the lamps are switched off.
Several different types of lamp covers and their drive mechanisms have been suggested. Examples include Japanese Laid Open Utility Model Applications Nos. 59-163537 and 59-163538. A problem common to these known devices is that the lamp cover, pivoted on the lamp housing for covering and uncovering the front lens, is geared more or less directly to the electric reversible drive motor. Being constantly exposed to atmosphere, however, the lamp cover is susceptible to jamming as by snow or ice. If the drive motor is energized when the lamp cover is so locked against movement, either the motor or the gearing has been subject to destruction through overloading.